Error "Failed to get field handle to set library path" when using Java 12

[martinschneider]

When calling OpenCV.loadShared();:

java.lang.ExceptionInInitializerError
	at nu.pattern.OpenCV$SharedLoader.getInstance(OpenCV.java:232)
	at nu.pattern.OpenCV.loadShared(OpenCV.java:181)

Caused by: java.lang.RuntimeException: Failed to get field handle to set library path
	at nu.pattern.OpenCV$SharedLoader.addLibraryPath(OpenCV.java:258)
	at nu.pattern.OpenCV$SharedLoader.<init>(OpenCV.java:206)
	at nu.pattern.OpenCV$SharedLoader.<init>(OpenCV.java:187)
	at nu.pattern.OpenCV$SharedLoader$Holder.<clinit>(OpenCV.java:228)

I think the problem lies in this line but I'm not entirely sure how to fix it.

Is this a known issue?

[vonnieda]

Hi @martinschneider, no, this isn't a known problem. This library tends to be a little bit fragile when it comes to new Java versions, so there is probably some tweaks that need to be made. If you are able to come up with a compatible fix that would be very welcome! Otherwise, I will look at this as soon as I have some time.

Thanks,
Jason

[Maurice-Mueller]

The same error for me. When I'm testing with OpenJDK 10 it is loading but I get the following warning:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by nu.pattern.OpenCV$SharedLoader (file:/home/maurice/.gradle/caches/modules-2/files-2.1/org.openpnp/opencv/3.4.2-1/fbd8f36fd1ce4e2bf0dcb12befd7d4cfc74d8d35/opencv-3.4.2-1.jar) to field java.lang.ClassLoader.usr_paths
WARNING: Please consider reporting this to the maintainers of nu.pattern.OpenCV$SharedLoader
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
OpenJDK 64-Bit Server VM warning: You have loaded library /tmp/opencv_openpnp2599240055310010051/nu/pattern/opencv/linux/x86_64/libopencv_java342.so which might have disabled stack guard. The VM will try to fix the stack guard now.
It's highly recommended that you fix the library with 'execstack -c <libfile>', or link it with '-z noexecstack'.

[rlking]

Instead of OpenCV.loadShared(); you can use OpenCV.loadLocally(); if it's appropriate for your project. In JDK10+ they restricted the reflective access so it won't work anymore.

[AuligPromotions]

I get the same error on Java 11.0.3. Problem is I need to use Java 11, so any ideas on how to fix this?

[vonnieda]

I have some changes in the works that will hopefully solve this problem permanently. I am looking at changing how the library is loaded to the same method that JNA uses, and this should remain compatible across JDK updates.

[martinschneider]

Thanks a lot for fixing this!

[vonnieda]

Two questions: 1. What operating system? 2. Can you show a log of the error happening? Thanks, Jason

…

On Tue, Feb 16, 2021 at 2:59 PM Ivan ***@***.***> wrote: I am still getting this error in JDK15 with Gradle, OpenCV 4.3.0-3. I would be very thankful for some assistance. Thank you. — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#44 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAJAU47TLZHR6UPD5XTHVNDS7LMCJANCNFSM4HIJVQUA> .